Patent GB-979771-A (GB)
Title: Process for dyeing and printing fibrous materials
IPC: D06P3/32
Filed: 1962-02-23
Abstract: Fibrous materials are dyed or printed by treatment with an aqueous preparation containing (a) 1 : 2-chromium or 1 : 2-cobalt complexes of azo or azomethine dyestuffs which contain at least one -SO3H or -COOH group imparting solubility in water and do not form covalent bonds with the fibrous material or with aminoplants and (b) water-soluble or at least dispersible aminoplants and curing the treated material in the presence of an acidic catalyst.  The fibrous materials may be leather or paper or fibres of glass, cellulose acetate, polyamide, polyurethane, polyacrylonitrile, polyester or especially cellulose fibres such as viscose rayon and cotton.  The metal complexes (a) may be formed from 1 atom of metal and two molecules of the same dyectuff, one molecule each of two different dyestuffs or one molecule of dyestuff and one molecule of a colourless complex former.  The dyes may contain one or more azo linkages or azomethine groups and the 1 : 2-metal complex preferably contains 2-4 -SO3H groups.  The dyestuffs while containing no reactive groups (including acid amide groups) may be substituted with, for example, methyl, methoxy, ethoxy groups, aromatically bound hydroxyl groups or chlorine atoms.  Specified complex-forming groups are o, o1-dihydroxyazomethine, o-carboxymethoxy-o1-hydroxyazo, o-carboxy-o1-hydroxyazo, o-carboxy-o1-aminoazo, o-hydroxy-o1-aminoaza and preferably, o, o1-dihydroxyazo groupings.  The preferred dyestuffs have one azo linkage and may be prepared in the usual way by diazotising o-carboxy-amines or o-hydroxyamines of benzene or naphthalene and coupling with aminonaphthalenes, hydroxybenzenes, hydroxynaphthalenes, 2 : 4-dihydroxyquinolines, pyrazolones or barbituric acid capable of coupling vicinal to an amino, hydroxyl or enolisable keto group.  Many aminoplants (b) are specified but those preferred are methylolureas and methylolmelamines which may be etherified with lower alcohols, e.g., methanol.  The aqueous preparations may also contain a latex of a polymerization plastic especially polymers of ethylenically unsaturated monomers or water-insoluble aminoplants.  A polyethylene emulsion is employed in the examples as a softener and many others are specified. Specified acidic catalysts are ammonium sulphate and chloride, diammonium phosphate, ethanolamine hydrochloride, zinc nitrate, zinc fluoborate and ammonium silicofluoride.  The aqueous preparations may also contain wetting or dispersing agents, usual thickeners and hydrotropic agents.  The preparations are preferably applied in a continuous manner e.g. by padding at 10-40 DEG C. or by roller printing.  Curing may be effected at 120-180 DEG C. preferably with previous drying at below 100 DEG C. except in the case of viscose rayon where the impregnated material may be left in the moist state for 1-6 hours before dyeing and curing. According to the content of the aqueous preparations additional effects of crease and shrink resistance, permanent calender, water repellency and modified handle may be obtained simultaneously.  The cured dyeings and prints may be soaped and rinsed.  Examples of dyeing and printing cotton and viscose fabrics are given.